/*
 * Copyright 2023 OceanBase
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { InputStream, Token } from 'antlr4';

const ANTLRInputStream = InputStream;

export default class CaseInsensitiveStream extends ANTLRInputStream {
  LA(offset) {
    const result = super.LA(offset);

    switch (result) {
      case 0:
      case Token.EOF:
        return result;
      default:
        return String.fromCharCode(result).toUpperCase().charCodeAt(0);
    }
  }
}
